A headlight, especially for motor vehicles, contains at least one optical system comprising a powerful light source and optical elements. The light source emits light rays and the optical elements represent a system of refractive and reflective surfaces, interfaces of optical environments and diaphragms that influence the direction of light rays within the creation of the output light trace.
The optical system of the headlight is mounted in a shaped holding bushing of the headlight. To ensure the desired function of the headlight, precise adjustment of the optical system is necessary, i.e. setting of the position of the light source with respect to all the optical elements. The optical system and its individual elements are first adjusted during the production of the headlights, when the setting of individual components depends on various design and assembly factors. The entire adjustment of the optical system is subsequently done by means of adjustment elements of various designs, which must be accessible from the outer side of the headlight. The optical system is mostly adjustable on two axes by means of a mechanical and/or electric adjustment system.
In the prior art, a number of adjustment systems are known allowing adjustment of the optical system in the horizontal and vertical direction to compensate any assembly deviations of the vehicle body and variable operational loading of the vehicle. The adjustment system of the optical system is most frequently implemented through three-point mounting while one point is generally fixed and two points are sliding, generally consisting of ball or cylindrical mounting. These three assembly points then make it possible to adjust the light unit in the horizontal and vertical position within the headlight.
E.g., the documents DE102006008193A1, FR2760069A1, FR2838809A1, and FR2807982A1 describe various designs of the adjustment system to achieve the desired characteristic of the optical system of the projection unit. A disadvantage of these designs is the fact that around the output lens of the projection unit there must be a free space to ensure adjustment of the optical system and free movement of the output lens. Each of the headlights emits light to a certain delimited space which is manifested in such a way there is a different free space between the fixed part of the headlight as the covering mask or holding bushing and the movable output lens. Then, from the front view the output lenses are not situated in parallel, but one lens deviates from the parallel direction of the other one. From the point of view of style, output lenses situated in a non-parallel direction represent a disturbing design element where the output lenses either converge or diverge.
The document CZ301707 discloses an adaptive system of headlights of motor vehicles with a projector unit that is vertically and horizontally adjustable by means of actuators for vertical and horizontal movement. The projector unit has a diaphragm in a frame, consisting of two movable segments, where the segments of the diaphragm are controllable by the actuators, while a diaphragm segment is fixed with respect to the diaphragm frame, and the entire projector unit can be moved vertically by means of an actuator with respect to the holding bushing and covering glass.
In modern headlights of motor vehicles, light sources consisting of LED light units are frequently used. An advantage of LED light units is their durability, small dimensions and the possibility of horizontal arrangement in systems perpendicular to the light axis of the headlight, in vertical and horizontal rows. During a drive of the motor vehicle, with the high beam on, individual light units or their groups or rows can be optionally switched off to produce a dark unlit part in the light pattern on the carriageway in the place where a camera mounted on the vehicle detects an oncoming vehicle. However, LED light units individually have a low light output, which can be increased by using a high number of LED light sources, but directing light beams from a higher number of LED light sources and creating a suitable light pattern is difficult and thus it still remains a technical problem.
In the operation condition, the light source arranged in a headlight emits a great amount of heat, which heats up the bushing and the cover of the headlight, as well as all parts that are found in the inner space of the headlight. The inner space of the headlight is further heated up by heat transfer from the other components of the engine compartment of the vehicle. Parts of a headlight, especially a motor vehicle headlight, get regularly heated up during vehicle operation and after deactivation of the light source they cool down, which causes undesired internal stress in the parts. A high temperature in the internal space of the headlight also has a negative impact on the luminous intensity of light sources.
The document U.S. Pat. No. 7,329,033B2 discloses a cooling design when the inner space of the headlight is connected to the external ambient environment and during air exchange hot air from the inner space of the headlight is exchanged with cold air from the external environment. However, unwanted dirt and dust penetrate into the inner space of the headlight through every opening in the bushing.
The document CZ2014-919 discloses the design of sliding or rotary mounting of a part of a cooling channel with a cooling element in the inner chamber, allowing subsequent adjustment of the position of the light source to achieve the desired radiation characteristic while the cooling channel is closed, and no undesired contamination of the cooling system occurs. A disadvantage of this solution is sliding and/or rotary mounting around two divergent or skew axes, and the adjustment system is thus geometrically sensitive to setup of the light units in space. If the adjustment system allows movement of the light unit only in the vertical or only in the horizontal direction, the setup of the light unit in space is less sensitive and simpler from the design point of view.
A goal of the invention is to eliminate the above mentioned shortcomings of the prior art. Another goal is to design a light system the adjustment system of which for achievement of the desired radiation characteristic is structurally simple and at the same time enables efficient adjustment of the optical system.